A reasonable criterion of nitrogen-doped single-walled carbon nanotubes with pyridine-like configurations

Abstract: Bond curvature K D as a universal criterion is used to identify structures and reactivities of N2-doped single-walled carbon nanotubes. Calculations of adjacent N2-dopings show that, as K D is large, a pyridine-like structure is formed and the formation energies E f linearly decrease with increasing K D, whereas as K D is small, the doping N–N bond cannot be broken. A boundary of K D between generating broken and unbroken N–N bond structures is about 1.6 nm−1. For the (n,0) tubes, the E f of products with the pyridine-like configurations have an odd–even oscillation rule with n values, and display a decreasing trend with increasing K D. As the largest value K largest among all K D in a given tube is small, two N atoms are inclined to disperse in the tube and its product has a perfect sp2 hexagonal network configuration. The approximate border value of K largest for the adjacent and disperse substitutions is 2.3nm−1. [Copyright &y& Elsevier]